Flow control device for refrigerating apparatus



Jan. 10, 1967 J. WEIBEL, JR, ETAL 3,296,816

FLOW CONTROL DEVICE FOR REFRIGERATING APPARATUS Filed April 10, 1964 2 Sheets-Sheet 1 John lLfeZbeJfimvENmRs.

Rickard i: Zl/Mdozusan HM ATTORNEY Jan. 10, 1967 J. WEIBEL, JR, ETAL 3,296,816

FLOW CONTROL DEVICE FOR REFRIGERATING APPARATUS Filed April 10, 1964 2 Sheets-Sheet 2 if ()Okl )A/flbe) Jr. INVENTORS.

Richard 5 lc/zdaoafsozz H15 AT'TORNEY United States Patent 3,296,816 FLOW CONTROL DEVICE FOR REFRIG- ERATING APPARATUS John Weibel, in, and Richard E. Widdowson, Dayton,

Ohio, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Apr. 10, 1964, Ser. No. 358,906 8 Claims. (Cl. 62-210) This invention pertains to refrigerating apparatus and more particularly to controlling automobile air conditioners.

Controlling automobile air conditioners is difficult. The controls must be inexpensive, compact and readily fit into cramped unoccupied space remaining in the engine compartment. The controls must feed adequate amounts of liquid refrigerant to the evaporator at all temperatures and at all car speeds and all speeds of the compressor. The temperature and the car speed will affect the need for cooling and the rate of evaporation of refrigerant in the evaporator. Provision must also be made for sufiicient refrigerant flow into and out of the evaporator during idling of the engine. The flow must be controlled in such a way that the evaporator will not frost and yet maintain a temperature as low as possible therein in order to obtain maximum capacity.

It is an object of this invention to provide an efficient, compact, inexpensive flow control device which will at all times supply all the refrigerant that the evaporator can beneficially use without discharging liquid refrigerant to the compressor.

It is another object of this invention to provide a compact, inexpensive flow control device which is controlled in response to the pressure between the suction line control valve and the compressor inlet.

It is another object of this invention to provide an efficient, compact, inexpensive flow control device which is controlled in response to the diiference in the pressure between the suction line control valve and the compressor inlet and the pressure in the evaporator.

It is another object of this invention to provide an efficient, compact, inexpensive flow control device which will provide minimum flow of refrigerant during idling conditions and the maximum flow which can be benefically used at all other times.

These and other objects are attained in the forms shown in the drawings in which a restrictor is used to provide a minimum liquid flow from the condenser to the evaporator at all times. A by-pass for this restrictor is provided which is controlled by a slide valve or a needle valve operated by a fluid motor which is responsive on one face to the pressure prevailing between the suction line control valve and the inlet of the compressor. The opposite face of the fluid motor is exposed to the pressure of the refrigerant within the evaporator. With this arrangement, either a rise in pressure in the evaporator or a fall in pressure between the suction line control valve and the compressor inlet or both will open the by-pass to provide increased refrigerant flow so that maximum capacity of the compressor is used as well as maximum capacity of the evaporator. The suction line control valve at the outlet of the evaporator assures that the pressure and the temperature within the evaporator are kept sufficiently high to prevent frosting thereof.

In a third type of liquid flow control device there is provided a piston valve including a restricted passage which under a high pressure differential connects in series with a second restricted passage to provide minimal flow. When the pressure differential is less, the piston valve will move away from the second restricted passage to permit additional liquid to by-pass the second restricted passage to provide increased flow.

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Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a vertical sectional view through a combined liquid flow control device and suction line control valve embodying one form of my invention taken along the line 1-1 of FIGURE 2 together with the remaining elements shown diagrammatically of the auto-mobile air conditioning system;

FIGURE 2 is a top view of the combined structure shown in FIGURE 1;

FIGURE 3 is a simplified form of liquid flow control device incorporating a needle valve and diaphragm and FIGURE 4 is another modified form of liquid flow control device.

Referring now more particularly to FIGURE 1, there is shown diagrammatically a compressor 20 which is customarily driven by the engine of the automobile through a belt and an electromagnetic clutch. This compressor has its inlet connected to the suction line 22 and its outlet connected to the inlet of the condenser 24. The outlet of the condenser 24 is connected to the inlet of the liquid control device 26 which has its outlet connected to the liquid supply conduit 28 connecting with the inlet of the evaporator 30. The outlet of the evaporator 30 is connected by the suction conduit 32 to the inlet of the suction 'line control valve 34 which is housed in the same housing 36 as the liquid flow control device 26. The outlet of the suction line control valve 34 is connected to the suction line 22 connecting with the inlet of the compressor 20.

The suction line control valve 34 includes an inlet fitting 38 containing an inlet passage 40 leading to a piston valve 42 slidably mounted within the double cylinder housing 44. The lower end of the double cylinder housing 44 has a beveled rim resting upon a gasket 46 mounted on a shoulder of the inlet fitting 38 for sealing the cylinder member 44 to the inlet fitting 38. The cylinder member 44 extends through an opening 48 in the housing 36 and the inlet fitting 38 is sealed to the housing 36 surrounding the opening 48. The double cylinder member 44 is provided with a plurality of slots 50 in its sides above the lowermost position of the piston valve 42 which are progressively uncovered as the piston valve 42 rises under pressure in the inlet passage 40.

The piston valve 42 is provided with a central strainer 52 at the entrance of its hollow central portion which connects through a leakage path which includes the radial passage 54 and annular passages 56 and 58 which connect with the dash pot chamber 60 formed by the junction be tween the smaller cylinder portion 62 of the member 44 and the larger portion 64 thereof. The piston valve 42 has an enlarged upper portion 66 provided with a flexible plastic seal ring 68 which is U-shaped in crosssection and contains several tiny apertures. This seal ring 68 cooperates with the chamber 60 to form a dash pot which prevents hunting of the piston valve 42 and assures smooth operation.

The upward movement of the piston valve 42 is opposed by a light conical coil spring 70 having its lower end seated on top of the piston valve 42 and its upper end seated upon the plate 72 fitting on a shoulder in the upper portion of the enlarged cylinder portion 64 inside a seal ring 74. Resting upon top of the seal ring 74 and the perforated disk 72 is the out-turned flange 76 of an inverted cup-shaped member 78. A clamping ring 80 rests on top of the out-turned flange 76 to hold the out-turned flange 76 in sealing engagement with the seal ring 74 and in engagement with the adjacent edge of the disk 72. On top of the clamping ring 80 rests the lower end of a stiff compression type coil spring 82 which surrounds the inverted cup-shaped member 78 and has its upper end bearing against the in-turned flange 84 of the housing 36. The in-turned flange 84 connects directly to the outlet fitting 86 connecting with the suction line 22. The coil spring 82 holds the inverted cup member 78 and the double cylinder member 44 in place with its beveled rim sealed upon the gasket 46 surrounding the inlet passage 40.

The perforated disk 72 carries a bellows mounting member 88 and a bellows evacuating tube 90. The bellows evacuating tube 90 extends to the interior of a metal bellows 92 having its lower edge sealed to the bellows mounting member 88 and having an upper closed end 94 containing a spring retainer 96 supporting the upper end of a compression type coil spring 98, the lower end of which is seated on the bellows supporting member 88. This bellows 92 is evacuated so that it will be collapsed by a high pressure and expanded by the spring 98 at a lower pressure. It is exposed to the pressure prevailing within the inverted cup-shaped member 78 which through leakage is responsive to the pressure in the inlet passage 40.

Resting on top of the closed end 94 of the bellows 92, is a plastic valve member 121 having a frusto-spherical bottom surface and a cup-shaped inner valve seat which is adaptedto cooperate with the rounded end of the hollow screw 123 having a restricted passage extending down to its rounded lower end. This screw 123 is threaded through the top of the inverted cup-shaped member 78 and is locked in place by the lock nut 125. This screw 123 is accessible from the outlet passage 127 in the outlet fitting 86 for adjustment. The screw 123 is surrounded by a light compression type coil spring 129 having its upper end held by the top of the inverted cup-shaped member 78 and its bottom supported on the flange of the plastic valve member 121. The bellows 92 is shown holding the valve member 121 tightly against the bottom of the screw 123 so as to close the restricted passage in the screw 123 to prevent the escape of gas from the interior of the inverted cup-shaped member 78 surrounding the bellows 92.

The leakage past the piston valve 42 will tend to keep the pressure within the inverted cup-shaped member 78 substantially at the same pressure as the inlet passage 40. When this pressure rises to the desired minimum pressure to be maintained in the evaporator 30, the bellows 92 will be compressed to allow the valve member 121 to move away from the bottom of the screw 123 to allow a flow out of the inverted cup-shaped member 78 through the hollow screw 123 to reduce the pressure above the piston valve 42 to allow the piston valve 42 to open wider to reduce the pressure in the evaporator 30 to maintain the selected pressure and temperature. The selected pressure and temperature is adjusted by the adjustment of the screw 123.

The housing 36 is also provided with an inlet fitting 133 containing an inlet passage 135 connected to the outlet of the condenser 24. This inlet fitting 133 is sealed to an opening 137 in the housing 36. The housing 36 is also provided with an outlet fitting 139 containing an outlet passage 141 connecting with the liquid line 28. This outlet fitting 139 is sealed to the housing 36 surrounding the opening 143. The outlet fitting 139 is provided with a shoulder 145 containing a seal ring 147 on which rests the bottom of a cylinder member 149. This cylinder member 149 contains a piston valve or slide valve 151 surrounded by a plastic seal ring 153 which is U-shaped in cross-section and cooperates with the inner cylindrical wall of the cylinder member 149 to form a fluid motor.

Threaded into the bottom of the cylinder member 149 is a hollow stem 155 containing a long passage 157 connecting with the inlet passage 135 and a restricted passage 159 connecting with the outlet passage 141. The passage 157 is provided with a branch passage 161 connecting with a vertical slot 163 on the outer face of the stem 155. The piston valve 151 slides on the outer surface of the stem over the slot 163. The piston valve 151 is urged downwardly to a position covering the slot 163 against the bottom of the cylinder member 149 by a compression type coil spring 165 which at its lower end is seated on an outwardly extending flange of the piston valve 151 and at its upper end, is supported by the disk 167 which is threaded into an upper cylindrical member 169 which rests on top of the lower cylinder member 149. Both cylinder members are held in place by the heavy coil spring 171 which rests on the outer flange of the upper cylinder member 169 and at its upper end bears against the inner wall of the housing 36 surrounding the opening 137. The inlet fitting 133 has a cylindrical portion extending downwardly telescoping the upper end of the hollow stem 155 and extending over the seal ring 173. The housing 36 is made of sheet metal with an upper half and a lower half connected together at the outwardly turned flanges 175.

The 'bottom of the cylinder member 149 is provided with a plurality of drilled diagonal passages 177 extending from the annular chamber 179 formed between the piston valve 151 and the bottom of the cylinder member 149 to the outlet passage 141. The piston valve 151 is therefore subject to the difference in pressure between the chamber 179 and the pressure of the gas above it which has direct communication through the interior of the upper cylinder member 169 and the housing 36 with the pressure prevailing in the outlet passage 127 connecting with the suction line 22. When the suction line control valve 34 is throttling to such an extent that the compressor 20 is lowering the pressure in the suction line 22, there will be a correspondingly low pressure on top of the piston valve 151 to cause it to open because of the greater pressure in the chamber 179. That is, the piston valve 151 will open wider upon lowering of the pressure in the suction line 22. When the pressure within the evaporator is high, this will raise the pressure in the chamber 179 to assist in the opening of the piston valve 151 and the uncovering of the slot 163. The uncovering of the slot 163 will allow augmented flow of liquid refrigerant from the passage 151 through the passage 161 and the slot 163 to the chamber 179 and through the passages 177 to the outlet passage 141. This will augment the flow of liquid refrigerant through the restricted passage 159 by providing additional flow through this by-pass arrangement. Under normal operating conditions the piston valve 151 will uncover the slot 163 to a greater or lesser extent to provide suflicient flow to keep the evaporator 30 supplied with as much liquid refrigerant as it can beneficially use. The piston valve 151 will normally move to close the slot 163 when the automobile engine is idling and driving the compressor 20 at a very low speed. Under such circumstances a minimum flow of refrigerant is provided through the restricted passage 159. Through this simple arrangement the flow of liquid refrigerant is controlled.

In FIGURE 3 there is shown a modified liquid flow control device 220 similar in its system of control. It includes a valve body 222 having an inlet connection 224 adapted to be connected to the outlet of the condenser 24 and an outlet connection 226 adapted to be connected to the liquid line 28. The inlet connection 224 connects through an inlet passage 228 to the valve seat bushing 230 which is threaded into the valve body 222 between the inlet passage 228 and the diaphragm chamber 232. This valve seat bushing 230 includes a passage 234, the outlet of which is provided with a valve seat cooperating with the needle valve 236. The needle valve 236 is provided with a stem passing through the diaphragm follower 238 and held thereto by a light conical coil spring 240 located on the other side of the follower 238. This arrangement enables the needle valve 236 to align itself with the passage 234. The follower 238 is clamped by a clamping ring 242 to a diaphragm 244 of flexible synthetic rubber or plastic having an inner bead 246 clamped between the clamping member 242 and the diaphragm follower 238. The periphery of the diaphragm 244 is provided with an outer bead 248 which is lodged in a recess in the valve body 222 surrounding the diaphragm chamber 232.

The bead 248 is locked in place by the fitting 250 having an outwardly turned flange 252 pressing against the diaphragm 244 held in place by the turned in rim 254 upon the valve body 222. The diaphragm follower 238 also serves as a spring retainer for one end of the coil spring 256, the other end of which is held by the adjustable spring retainer 258 which is threaded in the fitting 250. This spring retainer 258 is provided with a hexagonal aperture which can be adjusted through the threaded pressure connection 260 at the outer end of the fitting 250. This threaded section 260 is adapted to be connected by a flare connection with tubing which will connect with the suction line 22 so that it is responsive to the pressure between the suction line control valve 34 and the inlet of the compressor 20.

The diaphragm 244 constitutes a fluid motor subject on its right face to suction pressure as prevails between the suction line control valve 34 and the inlet to the compressor 20 and to evaporator pressure on the left face. It is the equivalent of the piston valve 151 in FIGURE 1 which likewise constitutes a fluid motor subject to the same pressures. The diaphragm chamber 232 connects with the passage 262 to the outlet connection 226 connecting with the liquid line 28. To prevent the flow from being completely closed during idle conditions of the automobile engine and correspondingly slow compressor speeds, the valve 236 is provided with a constantly open restricted passage corresponding to the passage 159 by providing a transverse groove 264 across the face of the bushing 230 which will permit restricted flow even when the needle valve 236 is seated. The opening of the needle valve 236 will in effect provide a bypass for the groove 264. The valve shown in FIGURE 3 is a full equivalent of the liquid flow device 26 shown in FIGURE 1 and operates to control the liquid flow in substantially the same way.

In FIGURE 4 is a simplified form of liquid flow control device adapted to be housed within a straight tube 321. It includes a sleeve 323 having a hollow screw 325 threaded into its closed end 327 and locked by a lock nut 329. The sleeve 323 has an outwardly extending flange 331 fitting the interior of the tube 321 provided with an annular groove containing a seal ring 333 providing a seal between the interior surface of the tube 321 and the sleeve 323. Within the sleeve 323 is a piston valve 335 containing a central passage 337 which is held in the sleeve 323 by a C-type retainer 339. The piston valve 335 is provided with a groove containing a seal ring 341 providing a seal between the piston valve 335 and the sleeve 323. The piston valve 335 is urged to the left by a compression type coil spring 343 which engages the enlarged portion of the piston valve 335 at one end and the closed end 327 of the sleeve 323 at the opposite end.

The piston valve 335 is provided with a valve seat 345 at its small end which is adapted to seat upon the rounded end of the hollow screw 325. The passage 337 in the piston valve 335 is larger than the restricted passage 347 provided in the rounded end of the hollow screw 325. When the piston valve 335 has its seat 345 separated from the rounded end of the hollow screw 325 liquid refrigerant coming through the inlet end 349 of the tube 321 passes through the passage 337 into the interior of the sleeve 323 and some can also flow through the restricted passage 347 in the hollow screw 325 to the outlet end 351 of the tube 321. Whenever the valve seat 345 is separated from the screw 325 the restrictor 347 is by-passed by flow out of the sleeve 323 through an aperture 353 in the wall thereof to the outlet 351. This provides the condition for normal flow. However, to prevent flooding of the evaporator during idling conditions of the automobile engine, when the pressure ditferential on the piston valve 335 is high, the piston valve 335 will be moved to the right against the force of the spring 343 until the seat 345 engages the rounded end of the hollow screw 325. This will prevent any flow by-passing the restrictor 347 and require all the flow to pass from the passage 337 through the restricted passage 347 to the outlet 351. The inlet of the tube 321 connects to the outlet of the con denser 24 while the outlet 351 connects to the liquid line tube 28. The piston valve 335 constitutes a fluid motor responsive to the difference in pressures on its opposite sides controlling the lay-passing of the restrictor passage 347.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising valve means provided with pressure responsive operating means substantially responsive to the difference between the pressure in the evaporating means and the pressure between the suction line control valve and the inlet of said compressor, said pressure responsive operating means being oriented and connected to provide increased opening of the valve means in response to reduced pressure between said suction line control valve and the inlet of said compressor.

2. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising valve means substantially responsive to the difference between the pressure in the evaporating means and the pressure between the suction line control valve and the inlet of said compressor, said flow control device also having a restricted orifice bypassing said valve means to assure a minimal flow.

3. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising a valve means for controlling flow through its inlet and a fluid motor having opposite faces for operating said valve means, said fluid motor having one face exposed to and responsive substantially to the pressure between the suction line control valve and the inlet of said compressor and having an opposite face exposed to and responsive substantially to the pressure within the evaporating means, said valve means being connected to said fluid motor in an orientation to open wider in response tolowering of pressure between the suction line control valve and the inlet of said compressor.

4. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising a valve means for controlling flow through its inlet and a fluid motor for operating said valve means, said fluid motor having opposed surfaces with one of the opposed surfaces being exposed to and responsive substantially to the pressure between the suction line control valve and the inlet of said compressor and another of the opposed surfaces being exposed to and responsive to the pressure in said evaporating means.

-5. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising a valve means for controlling flow through its inlet and a fluid motor for operating said valve means, said suction line control valve having an outlet connected to said flow control device, said fluid motor being located in said device exposed to and located between and separating the connection with said suction line control valve and the outlet of said device.

6. Refrigerating apparatus including a compressor having an inlet and an outlet, a condenser having an inlet connected to said outlet and having an outlet, evaporating means having an inlet and an outlet, a suction line control valve connected between the outlet of said evaporating means and the inlet of said compressor, a flow control device having an inlet connected to the outlet of said condenser and having an outlet connected to the inlet of said evaporating means, said flow control device comprising means forming a constantly open restricted passage and a bypass for said restricted passage provided with valve means and a pressure differential fluid motor device for operating said valve means.

7. A flow control device including a body having an inlet and an outlet, means within said body containing a restricted passage between said inlet and outlet, valve means cooperating with said passage for contnolling fluid flow through said passage, a fluid motor within said body responsive to the pressure in said body between said passage and said outlet, said valve means being operatively connected to said fluid motor, one of said means being provided with a substantially smaller passage to provide a minimum flow when said valve means is in closed position.

8. A flow control device including a body having an inlet and an outlet, means within said body containing a restricted passage between said inlet and outlet, valve means cooperating with said passage for controlling fluid flow through said passage, a fluid motor within said body responsive to the pressure in said body between said passage and said outlet, said valve means being operatively connected to said fluid motor, one of said means being provided with a substantially smaller passage to provide a minimum flow when said valve means is in closed position, said body having an additional chamber associated with said fluid motor for varying the operation of said fluid motor to vary the operation of said valve means.

MEYER PERLIN, Primary Examiner. 

1. REFRIGERATING APPARATUS INCLUDING A COMPRESSOR HAVING AN INLET AND AN OUTLET, A CONDENSER HAVING AN INLET CONNECTED TO SAID OUTLET AND HAVING AN OUTLET, EVAPORATING MEANS HAVING AN INLET AND AN OUTLET, A SUCTION LINE CONTROL VALVE CONNECTED BETWEEN THE OUTLET OF SAID EVAPORATING MEANS AND THE INLET OF SAID COMPRESSOR, A FLOW CONTROL DEVICE HAVING AN INLET CONNECTED TO THE OUTLET OF SAID CONDENSER AND HAVING AN OUTLET CONNECTED TO THE INLET OF SAID EVAPORATING MEANS, SAID FLOW CONTROL DEVICE COMPRISING VALVE MEANS PROVIDED WITH PRESSURE RESPONSIVE OPERATING MEANS SUBSTANTIALLY RESPONSIVE TO THE DIFFERENCE BETWEEN THE PRESSURE IN THE EVAPORATING MEANS AND THE PRESSURE BETWEEN THE SUCTION LINE CONTROL VALVE AND THE INLET OF SAID COMPRESSOR, SAID PRESSURE RESPONSIVE OPERATING MEANS BEING ORIENTED AND CONNECTED TO PROVIDE INCREASED OPENING OF THE VALVE MEANS IN RESPONSE TO REDUCED PRESSURE BETWEEN SAID SUCTION LINE CONTROL VALVE AND THE INLET OF SAID COMPRESSOR. 